Zotac has a cheaper version of the giga
(linked in one of my earlier posts) which strips the discrete graphics and trades the blu-ray drive for a DVD drive. Looks to be about $200 less than the ID70. The ID72 sku is listed in my earlier zotac giga link but isn't at retail in the US quite yet.
With Ivy Bridge available and offering ~50% increase in GPU performance, I would hesitate to purchase a SB system with integrated graphics unless you need it right now.
It's only a matter of time until Zotac (and AsRock) updates their lineups with IVB. I'm actually suprised that Zotac is launching the ID72 right now without IVB. I would wait for an IVB mobile system with integrated HD4000 graphics.
i5-3570K, ASRock Z77 Pro4-m, Asus GTX660 TOP, 120 GB Vertex 3 Max IOPS, 2 TB Samsung EcoGreen F4, 8GB G-Skill @1.25V, Silverstone PS07B